Background & Aims: Zinc, as an essential trace element and antioxidant, plays a significant role in the glucose and insulin metabolism and altered zinc content seems to be one of the contributing factors in the pathogenesis of diabetes mellitus (DM). The altered levels of serum zinc content has been observed in diabetic patients and it was reported that low serum Zinc concentration is one of the major factors in inducing cardiovascular diseases in patients with DM. The purpose of this study was to investigate the effects of oral administration of zinc oxide nanoparticles instead of zinc sulfate supplementation on cardiomyopathy indexes (Troponin I and CK-MB activity) in rats with T1DM.

Materials & Methods: In this study, 120 male Wistar rats were divided into two major intact and diabetic groups. DM was induced by single dose of STZ (45 mg/kg as i.p.). Oral administration of ZnO nanoparticles and zinc sulfate were gavaged respectively at doses 1, 3 and 10 and 30 mg/kg for 56 days. Blood samples were taken from heart at 7, 28, and 56 days and concentration of serum glucose, Insulin, zinc, troponin I and the activity of the CK-MB were determined.

Results: The results of this study revealed that in diabetic rats, serum glucose concentration significantly increased (P<0.001) and insulin and zinc levels significantly decreased (P<0.001). Rats with DM showed increased level of troponin I and induced activity of CK-MB (P<0.001). Oral administration of ZnO nanoparticles at dose 3 mg/kg significantly lowered serum glucose level and induced zinc and insulin concentration (P<0.001). It also showed cardioprotective properties by reducing troponin I and CK-MB activity significantly (P<0.01). In contrast, ZnO nanoparticles at dose 10 mg/kg induced cardiomyopathy and revealed high concentration of troponin I and CK-MB (P<0.01). Zinc sulfate administration at dose 30 mg/kg has similar effects as ZnO nanoparticles (3 mg/kg) but not as exactly as seen on the ZnO nanoparticles.

Conclusion: Oral administration of ZnO reduced troponin I content and CK-MB activity in serum of diabetic rats, though this findings revealed cardioprotective effects of ZnO nanoparticles.